The present invention relates to methods for aiding periodontal tissue regeneration with compositions containing bioresorbable polymers, leachable solvents, and bioavailable drug actives.
Periodontal disease is a major concern in dentistry. Periodontal tissues are often lost with the progression of periodontal disease. Loss of periodontal tissue compromises the prognosis for retention of teeth in the dental arch, often creates an unhealthy environment in the mouth and may be unsightly.
Various methods have been used to facilitate regeneration of lost or diseased periodontal tissue. Periodontal barriers are sometimes surgically implanted adjacent the root of the tooth, or wherever tissue loss has occurred, by periodontal surgery to aid and guide tissue regeneration along the tooth surface where periodontal tissue regeneration is desired. Presently, these barriers are comprised of materials such as polytetrafluroethylene (PTFE) which is biocompatible and non-resorbable. The barriers are typically removed after 4-6 weeks by a surgical re-entry procedure. Resorbable barriers are also being investigated for potential use in periodontal guided tissue regeneration. For example, cross-linked collagen is being studied in this regard.
It is often difficult to obtain the periodontal tissue growth desired since the regeneration of periodontal tissue is variable. Moreover, surgical implantation of barriers can be associated with infection and inflammation. Infection and excessive inflammation can adversely effect tissue regeneration with the use of periodontal barriers for guiding healing. Therefore it would be beneficial to be able to treat the tissue regeneration site with antibiotics, anti-inflammatories, or other appropriate chemotherapeutic agents as required to facilitate periodontal tissue regeneration. Also, the use of carrier agents in conjunction with appropriate chemotherapeutic agents to enhance cellular uptake of the chemotherapeutic agents would be helpful in the regeneration of periodontal tissue.
A potential problem envisioned with the use of chemotherapeutic agents in conjunction with periodontal barriers is how to control and regulate the delivery and uptake of such agents to the tissue regeneration site over an extended predetermined period of time so as to obtain the desired periodontal tissue growth.
The use of microparticles containing chemotherapeutic agents, and their use as periodontal barriers and in methods for aiding periodontal tissue regeneration, are known being described, for example, in U.S. Pat. No. 4,685,883, issued Aug. 11, 1987 and U.S. Pat. No. 5,059,123, issued Oct. 22, 1991, both to Jernberg, both incorporated herein by reference in their entirety. In the former patent, the microcapsules are said to be deposited in the periodontal pocket or attached to a root surface of the tooth for treatment of the periodontal disease itself, and not incorporated into a barrier for aiding or guiding periodontal tissue regeneration. The latter patent uses periodontal barriers made of body compatible materials (said to include resorbable and nonresorbable materials and which may also preferably incorporate microencapsulated chemotherapeutic agents) to aid periodontal tissue regeneration, which barriers are taught to be surgically implanted by conventional techniques and sutured in place by use of body compatible sutures.
In spite of such research, there continues to be a need for improved compositions and methods for aiding periodontal tissue regeneration. It is therefore an object of the present invention to provide methods for aiding periodontal tissue regeneration which are easy to administer, comfortable for the patient, and/or avoid the need for suturing and/or subsequent surgery to remove the compositions. An additional object is to provide bioresorbable compositions effective for periodontal tissue regeneration which provide sustained release of drug actives while supporting regeneration of periodontal tissue. An object is also to provide methods for aiding periodontal tissue regeneration which eliminate the need to suture the compositions at the treatment site.
These and other objects of the present invention will become readily apparent from the detailed description which follows.
All percentages and ratios used herein are by weight unless otherwise specified.